I don't think "fare-paying passengers" is quite the description for the target market.
I don't normally defend mega-rich celebrities, but Richard Branson has a history of taking part in high-risk activities, and even if potential participants can't assess the dangers on an engineering basis, they ought to be able to look at who's doing it, and conclude that it's not like an Oprah Winfrey tour. And the lawyers will make sure that they do, really, understand that it's dangerous.
So I think what the regulators ought to be concerned with is the risk to non-participants, and that the costs of cleaning up after a private jolly don't fall on the public, and then let people take their own risks.